FINGERPRINTS

Chapter 14
FINGERPRINTS
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
History of Personal Identification
•
•
~ 8 AD: Deliberately impressed fingerprints
have been found on Chinese and Japanese
documents
1870’s: William Herschel British official
Required palm prints & impressions of right
index finger from locals in India for every
contract he made
History of Fingerprint Identification
Henry Fauld
• Wrote first article about fingerprint
ID: 1880, Nature magazine
• Used fingerprints to help Tokyo
police in burglary case
History of Personal Identification
Alphonse Bertillion
• French police expert
• Developed the first systematic method of
personal identification in 1883.
•
• 2 Parts
• Portrait Parle:
• a detailed verbal description of the subject’s physical
characteristics and dress
• Anthropometry:
• Detailed description and precise measurements of the
body, including full length photographs
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Bertillion Anthropometry
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
The Will West Case:
Downfall of the Bertillion System
• Will West was taken to Levenworth Prison
• Records clerk ran his Bertillion measurements and
found they closely matched another prisoner who
was serving a life sentence: William West
• Even the photograph of William West closely
matched new prisoner, Will West
• Fingerprints of both were taken and found to differ
• Value of fingerprint Identification was established
History of Fingerprint Identification
Francis Galton
• Asserted all fingerprints were unique and did not
change throughout life
• Categorized patterns of fingerprints into loops,
arches and whorls
• Developed a classification system that allowed for
a person’s fingerprints to be placed in smaller
groups
History of Fingerprint Identification
Juan Vucetich
• Devised a classification system still used
in most Spanish-speaking countries,
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
History of Fingerprint Identification
Sir Francis Henry
• Developed alternative classification system
that was adopted in England
• His system has been modified and still is in
use in the United States and Europe
• Used 5 classifications to put a set of ten
fingerprints into one of thousands of classes
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
1) R Thumb 2) R Index
16
The Henry
Classification
System
LWALAALLWL
16
6) L Thumb 7) L Index
4
2
3) R Middle 4) R Ring
8
8
8) L Middle 9) L Ring
2
1
5) R Little
4
10) L Little
1
The sum of the values of the white squares that
contain a Whorl (plus one) is the numerator of
the primary classification.
The sum of the values of the dark squares that
contain a Whorl (plus one) is the denominator of
the primary classification.
1) R Thumb 2) R Index
3) R Middle 4) R Ring
5) R Little
8
6) L Thumb 7) L Index
8) L Middle 9) L Ring
1
8+1
9
1+1 = 2
10) L Little
History of Fingerprint Identification
Widespread use in USA
• 1901 - The use of fingerprinting by the New
York City Civil Service Commission
• 1904 - The training of American police by
Scotland Yard representatives at the 1904
World’s Fair
• 1924 - the fingerprint records of the Bureau of
Investigation and Leavenworth were merged to
form the identification records of the new
Federal Bureau of Investigation.
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Fingerprint Principles
1.
A fingerprint is an individual characteristic because
no two fingers have yet been found to possess
identical ridge characteristics.
2.
A fingerprint will remain unchanged during an
individual’s lifetime.
3.
Fingerprints have general ridge patterns that permit
them to be systematically classified.
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Principle One
• Mathematically, the probability for the existence
of two identical fingerprint patterns in the world’s
population is extremely small.
• Besides theoretical calculations, of the millions
upon millions of individuals who have had their
prints classified, no two fingerprints have been
found to be identical.
Remember the Madrid Bombing mix-up?
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Princpile One
•The individuality of a
fingerprint is determined by
the careful study of its ridge
characteristics, known as
minutiae.
Figure 14–1 Fingerprint ridge
characteristics. Courtesy Sirchie
Finger Print Laboratories, Inc.,
Youngsville, N.C., www.sirchie.com
•It is the identity, number, and
relative location of these
minutiae that imparts
individuality to a fingerprint.
•There are as many as 150
minutiae on the average
finger.
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Fingerprint Minutiae
Fingerprint ridge characteristics
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Principle One
• Most Fingerprints recovered at crime scenes are partial prints,
showing only a segment of the entire print.
• Under these circumstances, an expert can compare only a
small number of ridge characteristics.
• In a judicial proceeding, an expert must demonstrate a pointby-point comparison in order to prove the identity of an
individual.
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Figure 14–2 A fingerprint exhibit illustrating the matching ridge characteristics
between the crime-scene print and an inked impression of one of the suspect’s
fingers. Courtesy New Jersey State Police.
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Principle Two
• Fingerprints are a
reproduction of
friction skin ridges
found on the palm
side of the fingers
and thumbs.
Figure 14–3 Crosssection of human skin.
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Structure of the Skin
Pore
Epidermis
Dermal papillae
Blood supply
Dermis
Nerve
Sweat gland
Hair follicle
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Principle Two
• The epidermis is the outer layer of the skin, while the
dermis is the inner layer of the skin.
• The dermal papillae is the layer of cells between the
epidermis and dermis,
• is responsible for determining the form and pattern
of the ridges on the surface of the skin.
• Once the dermal papillae develop in the human fetus,
the ridge patterns will remain unchanged throughout
life except to enlarge during growth.
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Principle Two
• Each skin ridge is populated with pores leading to
sweat glands from which perspiration is deposited
on the skin.
• Once the finger touches a surface, perspiration
along with oils, is transferred onto that surface,
leaving the finger’s ridge pattern (a fingerprint).
• Prints deposited in this manner are invisible to the
eye and are commonly referred to as latent
fingerprints.
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Principle Two
• Although it is impossible to change one’s
fingerprints, some criminals have tried to
obscure them.
• In order to form a permanent scar, the wound
has to penetrate 1-2 mm beneath the skin’s
surface.
• However, permanent scars provide a new set of
fingerprint characteristics.
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
John Dillinger
• Tried to destroy his own fingerprints by
applying acid to them. Prints recorded at a
previous arrest and compared to his
postmortem prints, show that his efforts were
unsuccessful.
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Mythbusters Artificial Fingerprint
http://www.youtube.com/watch?gl=BR&hl=pt&v=MAfAVGES-Yc
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Principle Three
• All fingerprints are divided into three classes on the basis of
their general pattern: loops, arches, and whorls (L.A.W.).
• Categorized by the presence or absence of a delta (triangular
intersection of ridges)
• An Arch has NO deltas
• A Loop has ONE delta
• A Whorl has TWO deltas
• 60 - 65% of the population have loops, 30 - 35% have whorls,
and about 5% have arches.
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Fingerprint patterns
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Principle Three: Loops
• A loop must have one or more ridges entering
from one side of the print, recurving, and exiting
from the same side.
• loop opens toward the little finger - ulnar loop.
• loop opens toward the thumb - radial loop.
• All loops must have one delta, which is the ridge
point at or directly in front of the point where two
ridge lines (type lines) diverge.
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Loop Patterns
Figure 14–5 Loop pattern.
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Principle Three: Whorls
• Whorls are divided into four groups: plain, central pocket loop,
double loop, and accidental.
• All whorl patterns have type lines and a minimum of two
deltas.
• A plain whorl and a central pocket loop have at least one ridge
that makes a complete circuit.
• The double loop is made up of two loops combined into one
fingerprint.
• An accidental either contains two or more patterns, or is a
pattern not covered by the other categories.
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Principle Three: Arches
• Arches are divided into two distinct groups: plain arches and
tented arches.
• The plain arch is formed by ridges entering from one side of the
print, rising and falling, and exiting on the opposite side (like a
wave).
• The tented arch is similar to the plain arch except that instead of
rising smoothly at the center, there is a sharp upthrust or spike, or
the ridges meet at an angle that is less than 90 degrees.
• Arches do not have type lines, deltas, or cores.
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
AFIS-Automated Fingerprint Identification
System
• Operates by anchoring position of
fingerprint and searching database
using two types of ridges:
• Bifurcations
• Ridge endings
• Database works by comparing
prints to find ones with same
number of ridges in relative
positions
• Most likely matches are displayed for comparison by a
fingerprint examiner
IAFIS
Integrated Automated Fingerprint
Identification System
• Entirely digital system
• Compares a person’s set of ten fingerprints
against a database of millions of prints in a few
minutes
• Problems of incompatibility of formats is being
solved by development of workstations that
generate input directly into system
Types of Crime Scene Fingerprints
• Latent or Invisible Prints - caused by the
transfer of body perspiration or oils present
on finger ridges to the surface of an object.
• Visible Prints (Patent Print) - a fingerprint
made when the finger deposits a visible
material such as ink, dirt, or blood onto a
surface.
• Plastic Print - a fingerprint impressed in a
soft surface.
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Detection and Visualization of Fingerprints
• Patent and plastic prints are generally easy to
discover
• Major challenge lies in attempting to recover
latent prints from crime scene
• Different surfaces present different challenges
• Locating and visualizing prints can be done:
• Reflected Ultraviolet Imaging System
• Powder dusting—regular powder and magnetic
• Chemical enhancement methods
Chemical Methods
of Fingerprint Visualization
• Iodine fuming
• iodine crystals
sublimate to iodine gas
• gas adheres to fats in
the fingerprint residue
• Ninhydrin
• used for developing on porous
surfaces
• reacts with amino acids
• Cyanoacrylate (superglue
fuming)
• reacts with ions in the
• Silver Nitrate
sweat residue
• reacts with amino acids,
proteins, and fatty acid residues
Fluorescence of Fingerprints
•
Fingerprint residues contain substances
that will fluoresce when exposed to
certain wavelengths of light
•
After cyanoacrylate fuming is done,
Rhodamine 6G, which is a dye, was
applied. This fluoresces and emits
yellow light
•
Argon laser aimed at print and photo is
taken using a special filter
Powders
• Powders can be applied with a brush or magnetic
wand
• When applied lightly to a nonabsorbent surface
adhere to perspiration residues and/or deposits of
body oils left on the surface.
• Powders come in different colors, are magneticsensitive, or are fluorescent to aid the investigator.
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Preservation of a Developed Print
• Once the latent print has been visualized, it
must be permanently preserved for future
comparison and for possible use as court
evidence.
• A photograph must be taken before any further
attempts at preservation are made.
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Transporting Prints
• If the object is small enough to be transported
without destroying the print, it should be
preserved in its entirety.
• Prints on large immovable objects that have been
developed with a powder can best be preserved by
“lifting” with a broad adhesive tape.
• Then, the tape is placed on a properly labeled card
that provides a good background contrast with the
powder.
FORENSIC SCIENCE
An Introduction
By Richard Saferstein
PRENTICE HALL
©2008 Pearson Education, Inc.
Upper Saddle River, NJ 07458
14-*
Comparison of Prints
• Crime scene prints compared to
known prints
• Ten print card: used to collect
fingerprints
• Rolled print: fingerprint rolled
from cuticle to cuticle
• Tap prints: fingerprints that are
tapped in ink and then placed at
bottom of ten print card
Digital Fingerprinting
• Live Scan: 1990’s
• replaces inked ten print card
• captures friction ridge image and stores
digitally in computer database
International Association for Identification
• Umbrella group of fingerprint experts
• Decided in 1990 no standard minimum number of
points would be necessary for positive
identification
• Three level of friction ridge details would be used
to identify prints
Levels of Friction Ridge Details
• Level 1
• general features and patterns
• can be used to exclude a print only
• Level 2
• includes particular ridges (minutiae) in same place that
allow individualization of an unknown print
• Level 3
• requires low power microscope
• identifies minute imperfections, such as scars, edge shapes,
sweat gland pores
• so unique their presence virtually assures individuality